Next man up: Time doesn’t stand still in the NFL. So when a player can’t get on the practice field because of injury, his job is up for grabs.

That’s what appears to be happening with safety Usama Young. The free agent acquisition from last year has not practiced since Aug. 2 because of hamstring problems. The person benefitting is David Sims.

Sims has come out of nowhere to put himself into position to grab one of the last roster spots. He is listed as the No. 3 strong safety behind T.J. Ward and Young.

Taking advantage of increased play time with the second-team defense, Sims has recorded interceptions in both preseason games to co-lead the NFL in that category. He also is second on the team with five tackles and two other pass breakups.

In Detroit, Sims’ interception preserved the Browns’ 19-17 win. In Green Bay, his interception and 38-yard touchdown return set off a 35-10 Browns’ rout.

And then at Monday’s practice, Sims intercepted Brandon Weeden and Seneca Wallace in the span of 10 minutes, which earned him the focus of the assembled media afterwards.

“I think he’s flashed for the coaches, too,” said coach Pat Shurmur. “He’s challenging, he’s physical and he’s really made a huge amount of progress in the time we’ve been together.

“I’m hopeful that it’ll continue in the next two preseason games. That’s the kind of thing you want to see for a guy to make the team. He’s got to flash and got to make plays. To his credit, he’s done that.”

Black Bubba: Sims has acquired some nicknames from his new teammates. They have nothing to do with his ball-hawk ability but rather his compact, muscular upper body. He is 5-9 and 210 pounds.

“The only thing they call me is Big Swole, or Baby Bubba, or Black Bubba, because Bubba is jacked,” Sims said.

Bubba is the nickname of fellow backup safety and special teams core player Ray Ventrone, whose “jacked” arms are legend in the locker room. Sims said the two interceptions at practice were more of a surprise to him than the ones in the games.

“Actually I never really, ever, got interceptions in practice,” he said. “I can count them on my one hand in my career. I had to develop over the years to be a practice player so that I could take that to the game. I always made plays in games.

“I played running back in junior college. Always a return guy, so I’ve always had the ball in hands. I’m an offensive player at heart,” he said.

Sims converted to safety at Iowa State. He was signed last year as an undrafted free agent by the Giants, waived on the last cut, then signed by Tampa Bay in November and waived three days later. The Bucs were going through long snapper issues; Sims was added after the Bucs waived Christian Yount, who eventually replaced Ryan Pontbriand here. The Browns signed Sims to their practice squad 3 ½ weeks later.

Hungrier the third time around: Sims said his original release by the Giants still affects him. The first cut is the deepest.

“It hurt me because I know I’m good enough to play,” he said. “They had me questioning my ability to play a little bit after I got cut. But I still worked out and trained to be ready.”

Besides playing on the second team defense and all the sub defenses, Sims is on every special teams. Making the final roster isn’t the absolute long shot for him as it appeared when camp started.

Young was signed last year to a three-year contract for $6 million. The team actually would save about $1.05 million on its salary cap in 2012 if Young was not retained.

“Unfortunately, Usama got banged up, but the opportunity’s there for me and I’m gonna make the most of it,” Sims said.